The present invention relates to a semiconductor device and can suitably be used for, for example, a semiconductor device having a built-in an analog-to-digital converter.
A radio frequency circuit (RFIC) is equipped with an ADC (Analog to Digital Converter) for converting received analog signals to digital signals. The ADC is used to digitize an interface between the RFIC and a digital baseband LSI. As the ADC, for example, a Delta-Sigma ADC is used. In the case of the Delta-Sigma ADC, it is known that, when the amplitude of an input signal is small, for example, less than 10 mVppd, a spurious tone which is called an idle tone is generated. The idle tone deteriorates communication characteristics of the RFIC. Thus, in order to reduce the idle tone, a method of applying a dither signal to the Delta-Sigma ADC is known.
In Patent Document 1, there is disclosed a control method that detects the amplitude of an input signal to the ADC and changes the amount of dither signal to be applied to the ADC.